I have been doing a lot of research on the Catholic Church and evolution lately (see this post) and have found quite a bit of interesting material that I had previously been unaware of. We are all aware that Humani Generis (1950) gives some leeway for Catholics to entertain the possibility that the human body alone may have evolved from preexisting matter. I personally don't see how this is consonant with what Vatican I taught, that "If anyone does not confess that the world and all things which are contained in it, both spiritual and material, as regards their whole substance, have been produced by God from nothing, let him be anathema" (Canons on God the Creator of All Things, canon 5). Vatican I seems to be sayins that all creatures, even in their materiality, were created in their "whole substance" from God immediately. This seems to rule out any idea of God creating the material aspect of man and then, at some later point, infusing the spiritual element directly.
I decided to reread the Syllabus of Errors and Lamentabili Sane of St. Pius X and see if anything in these syllabi contained any references to evolution, and I was surprised to find two statements in the latter document that could be brought to bear on the debate. But first, let me preface this with some references to modern popular Catholic takes on evolution and creation.
For many Catholics, the question appears pointless because the objection is given that evolution is a problem of science, and the Church cannot properly make judgments in the realm of science, only on things that pertain to faith and morals. Then it is usually pointed out that there can be no real divergence between faith and true science (which is true), and hence we need to have no fear of "updating" our understanding of the traditional dogmas in light of the advances of modern science. This is the message of the Catechism (CCC 159) and of Catholic apologist Mark Brumley, who in a Catholic.net article stated that the evolution of the body was not properly the realm of faith but of science, and hence we have nothing to fear by postulating an evolutionary origin for the body (source).
I find it hard to explain how this is congruent with the perennial Catholic doctrine that man is a composite being, a body and soul united intimately. Man has but a single substance (human nature), and that very nature is to be an enfleshed spirit. If this composite being, which is man, has but a single substance, how can we postulate that the different parts of this being could have completely different origins? Furthermore, how could we hold that it is a matter of faith that man is a composite body-soul being, that the soul was created directly by God, that man as to his "whole substance" was created ex nihilo, but then go ahead and say that the body could have evolved, adding to this that it is not a matter pertaining to faith? If man is indeed a composite being with a single substance, then the origin of the body is very much a matter pertaining to faith.
Let's look at the pertinent quotes from Lamentabili Sane of 1907. First, in article 5, the following preposition is condemned:
Since the deposit of Faith contains only revealed truths, the Church has no right to pass judgment on the assertions of the human sciences.
Isn't that interesting! Pius X is telling us that the fact that the Church's de fide teaching extends only to matters of faith and morals does not therefore mean that it cannot weigh in on matters of science. Therefore, whether or not evolution pertains to faith directly is not essential to the argument. The Church can indeed pass judgments on scientific theories in totu, whether or not they pertain directly to faith and morals.
More interesting is article 64, which condemns the following:
Scientific progress demands that the concepts of Christian doctrine concerning God, creation, revelation, the Person of the Incarnate Word, and Redemption be re-adjusted.
Pius X here tells us that our doctrine about creation (among other things) need not be re-adjusted based on scientific progess. But is that not exactly what contemporary Catholicism has been trying to tell us, though? That we need to reevaluate our doctrines in light of modern scientific advances? After all, truth can't contradict truth. That may be the case, but "truth can't contradict truth" has too often become a mantra of those seeking to overthrow the traditional cosmology with one completely friendly to Darwinist evolution, and Pius X tells us that we ought to feel in now way compelled to do this.
Too often people take a concession of the Church and run with it as the norm. If a father tells his son he can take the car out only one night of the week and only under certain conditions, this is the language of concession, which implies that the norm (i.e., what goes on the other 6 days out of the week and under normal conditions) is that the son does not take the car out. If Pius XII tells us in Humani Generis that it is permissible to entertain the idea of the evolution of the body, and even then under only certain parameters, then we ought to realize that this, too, is the language of concession, and that it implies that the regular course of things demands that we adhere to the traditional understanding of instantaneous creation.
More on this later...